More people may be able to get the flu vaccine (search) in early January.

According to the CDC, the flu vaccine can now be given to adults aged 50-64 and close contacts of people in high-risk groups.

Depending on the availability of the flu vaccine, which is up to state and local health authorities, people in the new, expanded priority list will be eligible for vaccination beginning in January, says the CDC.

Earlier this year, short supplies triggered long lines for the flu vaccine. The shortages stemmed from manufacturing problems at a Chiron Corp. vaccine plant in Britain. As a result, the U.S. stood to lose about 48 million doses -- half of the country’s supply.

The scarce shots were restricted to people in the highest-risk groups for serious complications including:

People aged 65 and older Kids aged 6-23 months Pregnant women People of any age with health conditions such as heart disease, lung disease, or AIDS Transplant recipients Health care workers

Those people are still first in line.

“We urge persons in priority groups to continue to seek vaccination,” says CDC director Julie Gerberding, MD, in a news release. High-risk people “really should get a flu shot this year and we’re working hard to make sure it’s available in your community,” she says.

Midseason estimates of vaccination rates are below rates from last season for adults in priority groups, says Gerberding.

To give them a little more time, the current flu vaccine restrictions stay in effect through December. But so far, some areas have had less demand than expected from high-risk patients.

“We don’t want those doses to go to waste, so some states are expanding to make good use of those doses,” says Gerberding.

So far, the flu season has been mild. But that could change at any time, the CDC warns.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: News release, CDC. WebMD Medical News: “U.S. Loses Half Its Flu Vaccine Supply.” CDC, “Who Should and Who Should Not Get a Flu Shot?”